The move on Friday marked the first direct military action the US has taken against Syrian President Bashar al-Assad's forces in the country's long-running war, now in its seventh year.

As the world reacts to the US strike, Marwan Bishara, Al Jazeera's senior political analyst, offers his view on the latest developments in Syria.

US attacks Syrian airbase

What prompted the US to take direct military action against Assad's forces?

Marwan Bishara: Publicly, the US administration justified its response on humanitarian grounds and "vital national security interests".

I doubt there's much currency to either.

If President Donald Trump cared so much for Syrian children, he would not have barred them from entering the US. As for security, the chemical attack - horrible as it, maybe - is of no threat to vital US national security.

If, on the other hand, it was established that ISIL or al-Qaeda had carried out the attack using sarin gas, then there would be ground for concern to US forces in the area.

This was both a win-win strategic and political step by the Trump administration. The "proportionate" military response is meant to shore up Trump's popularity in the polls and to project an image of boldness and decisiveness.

It's a pinprick attack that's designed as a low-risk response that puts the Syrian regime on notice, increases the heat on Russia and opens the way for a more substantial US involvement in shaping the future of Syria.

It also establishes Trump's independence from Moscow and helps remove some of the suspicion of his alleged shady relationship with Russian President Vladimir Putin.

Russia's condemnation of the US response, followed by the decision to suspend its coordination with the US air force over Syria, will eventually work in Trump's favour as tensions subside.

Did Trump come up with this all on his own?

Bishara: Absolutely not. Despite his insistence that he knows more than the generals, Trump has proven ignorant and out-of-his-depth on strategy and foreign policy.

As the commander-in-chief, he's the one to give the order - but it was the generals he appointed to his cabinet that are behind this decision and others in the future.

As I see it, Defence Secretary James Mattis, Homeland Security chief John Kelly and National Security Adviser H R McMaster are the trio in control of US national security policy.

James Mattis, left, and H R McMaster

Unlike ex-President Barack Obama, Trump has thus far placed his trust in the generals he appointed.

The three are veterans of the US wars in Iraq and Afghanistan. They are known for their boldness and strategic intellectualism and unconventionality.

So when Mattis insisted that torture was counterproductive and America would not torture, Trump backed down on his campaign pledge to go beyond waterboarding.

Homeland Security Secretary John Kelly [Luis Soto/AP]

And when White House strategist Steve Bannon overstepped his boundaries by recommending a ban on Muslims without previous consultation, Kelly - along with the other two generals - ousted him from the National Security meetings.

That's why it seems to me that after taking their time, the trio are now articulating the strategy in both Syria and Iraq. It remains to be seen what other steps they have in mind.

What's the endgame now that the attack has been carried out?

Bishara: In strategic and political terms this has been a low-risk, high-yield scenario for the Trump administration. It has shored up the president's popularity among many Democrats and the mainstream media and earned much praise from regional and international powers.

Already, Turkey, Saudi Arabia and Israel, as well as Britain, the European Union and Australia, among others, have come out in support of the US attack.

It showed that Trump could and would act more boldly than his predecessor when needed. And that he won't go to Congress before carrying out such an attack.

Although limited in focus and nature, the US army's attack on Shayrat airfield paves the way for more of the same military actions - and that will improve US leverage in future negotiations over Syria.

It also demonstrated to Russia and Iran that the US must be taken seriously moving forward in Syria, and proved that Trump doesn't require an absolute proof of culpability of the Syrian regime over chemical attacks in order to punish it.

This is especially important because the punitive attack came against the backdrop of Secretary of State Rex Tillerson's claim shortly after this week's chemical attack that "steps are under way" to form an international coalition to remove Assad.

In other words, if the military response is only part of a wider strategy to establish safe zones and eventually remove Assad from power, then we are certainly on the brink of major transformation of US policy in Syria and beyond.

The timing of this attack also coincided with the visit by Chinese President Xi Jinping to the US.

It might create some tensions, but it sends a message about North Korea ahead of US-China talks in Florida.

Trump warned last week that Washington could act alone if Beijing did not put the necessary pressure on North Korea to halt its nuclear and missile programmes.